For the present illumination devices, they are usually assembled with a lighting assembly to project at least one illumination light beam to provide the function of illumination. In practice, the light emitting diodes (LEDs) can provide the performances of high power, high illumination, low power consumption and long life of use, so that the LEDs are usually applied to manufacture the illumination devices.
Actually, the LEDs also release heat energy when projecting illumination light beams to external environment. In the most conditions, if the heat energy can not be effectively dissipated, it not only influences the normal operation of the LED, but also decreases the life of use, and causes great decay of light; even more, it will make the LEDs be damaged soon. Therefore, the most illumination devices are usually assembled with a thermal module assembly, so as to increase the efficiency of heat dissipating through the improvement of the structure or the material of the thermal module assembly.
For raising the efficiency of heat dissipating, in structural, the thermal module assembly is usually designed with large surface area. However, it will make the overall structure of the thermal module assembly be more complicated if the surface area is increased. Thus, the manufacturing processes will become more complicated and, the yield rate will be become lower, and the manufacturing cost will also be increased. Under this background, the inventor has ever disclosed that a thermal module assembly can be manufactured by a plurality of heat dissipating fins arranged and fixed in a ring-distributed position.
Following up, a thermal module assembly provided by the inventor in previous will be further disclosed as a representative prior art. Please refer to FIG. 1 to FIG. 3 illustrating a method to manufacture the chain-connected type thermal module assembly in prior art, wherein FIG. 1 illustrates a thermal module assembly is composed of a plurality of heat dissipating fins and a fixing ring; FIG. 2 illustrates the heat dissipating fins arranging around a central axis in a ring-distributed position and being hitched by a fixing ring; and FIG. 3 illustrates that the fixing ring is compressed by an external force, and recessed toward the central axis to fix the heat dissipating fins. As shown in FIG. 1 to FIG. 3, a thermal module assembly 1 comprises a plurality of heat dissipating fins 11 being chain-connected, and each of the heat dissipating fins 11 comprises an extended folded plate 111. The heat dissipating fins 11 are arranged around a central axis A1 in a ring-distributed position. In other words, the heat dissipating fins 11 are radially extended from a central region C1 where the central axis A1 passes through.
The thermal module assembly 1 further comprises an inner fixing ring 12, and the bottom of the inner fixing ring 12 has an inner protrusion ring 121 protruded toward the central region C1. When assembling the thermal module assembly 1, firstly, it is necessary to make the heat dissipating fins 11 be arranged around a central axis A1 in a ring-distributed position, then it is necessary to make two ended ones of the heat dissipating fins 11 be adhered by tin soldering paste and fixed by reflow soldering, and make the fixing ring 12 hitch the outer side of all the heat dissipating fins 11. Following up, applying compressive forces on the fixing ring 12 with respect to the gaps between all neighboring two of the heat dissipating fins 11, so as to form a plurality of recessed structures 122. Hereafter, the recessed structures 122 and the inner protrusion ring 121 can fix the extended folded plates 111, so as to fix and position all the heat dissipating fins 11.
In practice, the heat dissipating fins 11 are usually made of aluminum alloy. For providing better performances in electrical insulation and antirust function, it is usually to execute an anodic treatment or an antirust treatment to form an anodic treatment layer or an antirust treatment layer on the surfaces of the heat dissipating fins 11. However, one who skilled in ordinary art can easily realize that there are four main problems existing in the prior art as mentioned.
First, due to that it is necessary to apply the compressive forces to the fixing ring 12, for ensuring that there will be no irregular deformation generating on the fixing ring 12 to influence the roundness of the fixing ring 12, it is further necessary to use more precision apparatus to apply the compressive forces, so as to increase the inconvenience of manufacturing.
Second, it is necessary to apply the compressive forces to the fixing ring 12 and ensure that there will be no irregular deformation generating on the fixing ring 12 to influence the roundness of the fixing ring 12. Thus, the fixing ring 12 shall be made of a material with sufficient hardness and malleability. In the prior arts, it is preferred to use white iron as the material with sufficient hardness and malleability; while, the environment conditions for executing the anodic treatment or the antirust treatment to the aluminum alloy is not suitable to execute such treatments to the white iron. Moreover, if the heat dissipating fins 11 are made of aluminum alloy, while the fixing ring 12 is made of white iron, the color of the heat dissipating fins 11 will be more obviously different from that of the fixing ring 12.
Third, due to that it is necessary to apply the compressive forces to the fixing ring 12, the roundness of the fixing ring 12 will be changed, even the change may be very slight. Therefore, the gaps between any neighboring two of the heat dissipating fins 11 will be not uniform. If the gap is too narrow, it will make the heat dissipating fins 11 be over tightened to generate unexpected deformation. On the contrary, if the gap is too wide, the heat dissipating fins 11 will become more loosening.
Fourth, due to that it is necessary to apply the compressive forces to the fixing ring 12, it is obvious that any neighboring two of the heat dissipating fins 11 will not keep in the same pitch distance. Therefore, the symmetry of the thermal module assembly 1 will be out of the predetermined requirement, and the appearance workmanship and overall performance of homogeneous heat conduction will also be out of the predetermined requirement.